In defence of polyethylene bags, shops can afford to give them
away because they are very cheap and this reflects the small amount
of resources consumed in their production. There lightness also
reduces transport energy costs. Such efficency in general is good
the environment. Hence, a levy on plastic bags has to be approached
carefully. By increasing use of alternatives it might increase resource
consumption and hence environmental impacts such as release of greenhouse
gases of use of wood products.
If such a levy was introduced, it should be done in away that we can
determine if its working. A must would be onoing surveys of marine
debris. These may also indicate other of debris sources which may
can be reduced. Measuring consumption of bag alternatives would also
be important.
I've seen one estimate that 1/1000 of polyethlene bags reach the
marine environment. If this is correct its likely more efficient to
attack the problem closer to the marine environment. For example, it
would be twice as cost-effective to spend $5 removing a bag from the
marine environment as 1c to stop a bag being used in the first place.
Measures which are possibly very cost-efficient include better trapping
of litter in stormwater drains and better control of litter around urban
estuaries and foreshores.
A number of personal actions have been mentioned. I've seen one estimate
that almost half of the release of bags into the environment is not by
the consumer but during the garbage disposal process, e.g blown away
from a landfill. So if you are disposing of bags its probably best to
do so in away that such release is less likely.
Andrew Taylor
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
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